The present invention relates to an electrical connection box mounted in a vehicle, such as an automobile.
Generally, electrical connection boxes have electric components, such as a wiring board, a fuse, a relay, and a connector. However, for example, an electrical connection box to be mounted in an automobile is sometimes installed in an engine room. Thus, such an electrical connection box takes a waterproof countermeasure to prevent electric components, such as a wiring board, from being short-circuited due to water caused by, e.g., an automobile wash to enter an engine room (see, e.g., JP-A-2002-152943).
As illustrated in FIG. 5, JP-A-2002-152943 discloses an electric connection box 101. A wiring board 103, on which a fuse housing 102 is mounted, is mounted in the electrical connection box 101 so as to be substantially perpendicular to a surface thereof. The fuse housing 102 has drainage grooves 104a and 104b and a water-stop wall 105. A drainage channel 106 is provided on the wiring board 103 so as to extend from the fuse housing 102 to a side end of the wiring board 103. Incidentally, reference numeral 107 designates an electric component such as a relay.
Water on the fuse housing 102 is caused by the wall 105 to flow along the grooves 104a and 104b without flowing out to the surroundings of the fuse housing 102. Then, the water flows along the drainage channel 106 leading to the side end portion of the wiring board 103. Finally, the water runs off. Thus, water on the fuse housing 102 does not run down from the fuse housing 102 along the surface of the wiring board. Consequently, the electric component 107 mounted below the fuse housing 102 can be prevented from being short-circuited due to water.
A drainage structure of the electrical connection box disclosed in JP-A-2002-152943 is configured so that water is discharged along a side end portion, on which neither wiring and nor electric components are mounted, in the wiring board 103. However, there is a fear that due to external factors, for example, vehicle vibrations and a negative pressure, water trickling along the side end portion of the wiring board 103 may run to the other part of the wiring board 103 until discharged completely, so that wiring or electric components may be short-circuited.
Incidentally, the drainage structure disclosed in JP-A-2002-152943 is provided on the inner side of the electrical connection box. However, even in the case where a drainage structure is provided on the outer side of the electrical connection box, when water is made to trickle along a side wall surface of the electrical connection box to run down, there is a fear that during water trickles along the side wall surface of the electrical connection box, the water may enter the electrical connection box and short-circuit internal wiring and electric components, due to the external factors, or to a capillary phenomenon occurring between a body and a lid for covering the body, both of which generally constitute the electrical connection box.